when i first got my car I didn't notice road noise or wind noise being excessive , but it's gradually been getting louder and louder, to the point where trying to listen to the radio without blasting it is useless so I've started driving with no music. The sound of the road and every bump being transferred to the cabin is mind-numbing and I've tried much more than I should have to in order to fix it.
I've added sound deadening mats like dynamat over absolutely everything but the ceiling and added Ensolite foam over all the doors and trunk and wheel wells. I changed to Pirelli P7 Grand Touring tires which were, as you said, among the top rated and quietest, but they're not cheap.
About $800 later, the deadening and tires did make a noticeable impact, but nowhere near what I'd call acceptable. I went on a drive with one of the ford mechanics today and he said he didn't think it was excessive. It didn't help that it was especially windy today.
I've been looking into anything and everything I can to quiet this car down and the best info I've come across is that it's just a cheap car. I really don't understand why any manufacturer would make a car that's this loud at highway speeds and not see it as a problem. Plenty of people say their Focus is the quietest car they've been in but I can't imagine how. I used to drive a BMW M3 with a loud exhaust and it was much quieter than this car on the highway.
Long story short, I have the same issue on my 2014 Focus SE with the Sport Appearance Package and I'd hate to see you waste your time and money like I did. I'm on the quest of selling the car and getting a slightly sporty German car. Fuel efficiency be damned, I need peace.
Edit: I've been thinking it might be a wheel or axle bearing and am dropping the car off at the dealer tomorrow morning to check it out, hopefully replace something. For whatever reason, Focuses of all generations seem to wear wheel bearings a lot without normal bearing failure signs. I'll update if anything happens.
Edit 2: The dealer found nothing wrong with the mechanics of the car but did note that there was a lot of wind noise, so I'm not completely crazy.